We are a small regional ITSP that uses Asterisk at a colo facility to provide virtual PBX services to business customers. Our end users use SIP phones (Polycom, Snom) with G729A. We use SIP trunks (Vitelity, Bandwidth.com). We are configured in a "multi-tenant" setup where each customer is a "virtual" PBX within the single Asterisk install. Asterisk is configured to use MySQL for the CDR and voicemail config, otherwise the config is all text-file based (main config files which include customer-specific files). We're currently using Asterisk 1.4, installed and built from source with DAHDI. The current server is Centos 5.5 64-bit.

Goal:

Our goal is to arrive at a primary/secondary HA server scenario where the primary server is always the master until it goes down, then the secondary takes over. I'm assuming we'd achieve this with linux-ha/heartbeat, DRBD, and MySQL master-master replication but I would love to learn about any other (simpler) recommendations. We'...